Camptonectes burlingtonensis (Gabb, 1860)
GABB, W. M. 1860. Descriptions of some new species of Cretaceous fossils. Journal of the Academy of Natural Sciences of Philadelphia [2nd Series], 4 (3-9): 299-395, pl. 48. [p. 304, pl. 48, fig. 25]
1860 Pecten burlingtonensis Gabb, 1860
1885 Pecten (Syncyclonema?) perlamellosus Whitfield, 1885
1885 Pecten (Syncyclonema?) perlamellosus Whitfield, 1885
W. M. Gabb, 1860, plate 48.
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«P. BURLINGTONENSIS. PI. 48, fig. 26. Shell discoidal, as broad as high, marked by numerous, irregular, concentric folds; ears nearly equal. A very fine cast.
Locality and position.—"Brown sand," Burlington Co., N. J. Collection of the Academy. Prof. Safford has kindly sent me, for examination, a series of cretaceous fossils, collected by himself in connection with the geological survey of Tennessee. I have been able to identify but two new species, Volutilithes Saffordi and Cardium abruptum, nobis. The most interesting specimens besides these are two, a whole valve and part of another of Trigonia thoracica, S. G. M. These specimens are perfect in their markings, and show some important characters not heretofore published, and prove that it is not the same as T. alaeformis, Sow., as Dr. Morton thought after having published it. I shall thus characterize it :—» WILLIAM MORE GABB, 1860
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«Remarks.— This fairly large Camptonectes is characterized byits broad subcircular shape, left valve with large auricles of nearly equal size, and strong concentric ornament that extends onto the auricles. Specimens from the Anacacho Limestone conform closely to the concept of the species presented by Weller (1907). The species displays very fine divergent radial ribbing characteristic of Camptonectes, as well as concentric costae that are more strongly developed than typical of the genus. On the best preserved specimen from Texas (Figure 3.8), the divergent ornament is preserved on the internal mold in the beak area. In addition, a small piece of original shell adhering to that specimen shows that the concentric undulations on the internal mold correspond on the shell exterior to lamellar plates that curve outward and downward to form round-crested hollow ridges.
Camptonectes (C.) burlingtonensis is a relatively common species in the Anacacho Limestone, where it has been found at several localities. It also occurs in the correlative Pecan Gap Chalk at locality M8702. This species has been reported from lower and middle Campanian units in New Jersey (Weller, 1907) and from the uppermost Campanian Coon Creek Tongue of the Ripley Formation in Tennessee (Wade, 1926). Dhondt (1972, p. 29) considered C. (C.) burlingtonensis to closely resemble C. (C.) virgatus (Nilsson, 1827), a species that ranges through the Late Cretaceous of Europe, but implied that the former is a separate species distinguished by its stronger concentric ornamentation.» ELDER, W. P. 1996. Bivalves and gastropods from the Middle Campanian Anacacho Limestone, south central Texas. Journal of Paleontology, 70 (2): 247-271, figs. 1-8. [p. 254]
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Camptonectes (Camptonectes) burlingtonensis (Gabb); W. P. Elder, 1996, Bivalves and gastropods from the Middle Campanian Anacacho Limestone, south central Texas, figures 3.11-3.16.
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«This species is common at Coon Creek and is represented in the collections by perfect specimens that show all the shell characters of both valves. The external sculpture shows much variation. Usually the sharp concentric lines are more widely spaced on the left valve than they are on the right. The byssal notch on the right valve is very deep and is serrate at its base. The adductor scar is subovate and situated in the upper half of the valve near the hinge.
Occurrence: Ripley formation, Dave Weeks place on Coon Creek, McNairy County, Tenn. Collections: New Jersey Geological Survey, Philadelphia Academy of Natural Sciences, U. S. National Museum. Outside distribution: Monmouth group, New Jersey.» WADE, B. 1926. The fauna of the Ripley formation on Coon Creek, Tennessee. United States Geological Survey Professional Paper, 137: 1-272, pls. 1-72. [p. 63, 64]
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Pecten burlingtonensis (Gabb); B. Wade, 1926, The fauna of the Ripley formation on Coon Creek, Tennessee, plate 20, figures 5, 6, 10, 11.
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«Description. — Shell, in large individuals, attaining a height of 57 mm., and a width of 62 mm.; the hinge-line straight, onehalf or a little less than one-half the width of the shell, with a central triangular cartilage pit; the body of the shell broadly subovate in outline, the auriculations moderately large and nearly equal in size; the cardinal slopes a little concave, diverging from the beak at an angle of 90 or more, the shoulders of the valves prominent and above the middle of the height of the shell. Left valve depressed convex with the auriculations sharply differentiated. Right valve nearly flat, with a moderately deep byssal sinus. Surface of the valves marked by concentric bands which are continuous across the auriculations, and by exceedingly fine, impressed, radiating striae which are continuous upon the auriculations and the umbo, where they are about equal in width with the interspaces, but on the outer portion of the shell they become more or less discontinuous, the inner portion of the concentric bands often being nearly smooth, while on the outer portion they are completely striate, but with the interspaces between the striae broader than the striae themselves.
Remarks. — Whitfield has united Pecten bellisculptus Con., with Pecten burlingtonensis Gabb, but an examination of a large number of individuals in the recent collections of the Survey show the two species to be entirely distinct. The two forms have sometimes been considered as the opposite valves of the same species, but this cannot be so for one example of P. burlingtonensis has been examined which preserves the cast of both valves, and they do not essentially differ in the character of the markings although the right valve is much flatter than the left. In the present report P. bellisculptus is considered as synonymous with P. argillensis. The surface markings, even in internal casts, are usually sufficient to separate the two forms, the conspicuous feature of burlingtonensis being the concentric bands, the radiating striae usually being entirely wanting in the casts, while in argillensis the radiating markings are the conspicuous feature of the shell and can be detected upon the casts as preserved in New Jersey, as well as upon the shells themselves or the impressions of the exterior. The nearly flat right valve and the nearly equal size of the auriculations are other characters distinguishing burlingtonensis. This species is also never so high and narrow proportionally as argillensis, although some members of the latter species sometimes have nearly the same proportions as specimens of burlingtonensis. The two species occur together in both the Merchantville and the Woodbury formations, but burlingtonensis is more common in the Merchantville, while argillensis is the commoner species in the Woodbury, but wherever they occur there is not the least difficulty in separating them. Gabb's type specimen was from the Merchantville. Whitfield's figure 7 seems to be a member of this species with one ear injured, but its identity cannot be determined from the figure alone. Pecten perlamellosus Whit. is apparently only an immature example of P. burlingtonensis, these young individuals being closely similar to P. conradi except that the concentric bands are somewhat broader and continue in nearly full strength across the auriculations. Formation and locality. — Merchantville clay-marl, near Matawan (101), near Jamesburg (141), Lenola (163), Burlington (Gabb); Woodbury clay, Lorillard (102), near Haddonfield (183); Wenonah sand, near Marlboro (130). Geographic distribution. — New Jersey.» WELLER, S. 1907. A report on the Cretaceous paleontology of New Jersey. Geological Survey of New Jersey, Paleontology Series, 4: ix, 871 p., pls. 1-111. [p. 470-472]
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Pecten burlingtonensis Gabb.; S. Weller, 1907, A report on the Cretaceous paleontology of New Jersey, plate 49, figures 5-9.
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